This invention relates to a fuel cell electrode, a process for producing the same and a fuel cell using the same. The fuel cell electrode of this invention is particularly suitable for liquid fuel cells using a liquid fuel such as methanol, hydrazine, etc., and phosphoric acid electrolyte fuel cells.
In the liquid fuel cells using methanol or hydrazine as a fuel or the phosphoric acid fuel cells using phosphoric acid as an electrolyte, electrodes are generally constructed by forming an electrode catalyst layer on a porous electroconductive substrate such as carbon paper, etc. Thus, the electrodes take a double structure of the porous electroconductive plate and the electrode catalyst layer. The electrode catalyst is obtained by carrying one or more catalytic active components on electroconductive particles such as graphite particles. The electrodes having such a structure are usually produced by coating the electrode catalyst on the porous electroconductive substrate by using as a binder a waterrepellent substance such as polytetrafluoroethylene. Since the electrode catalyst layer is formed on the electroconductive substrate via the coating step using the binder, there are problems in that the electrode catalyst layer is easily cracked and easily peeled off from the substrate.
Japanese Patent Appln. Kokai (Laid-Open) No. 124864/82 discloses an fuel cell electrode having such a structure as prior art technology. It also describes that the electroconductivity of the catalyst layer is so bad that a drop in voltage cannot be ignored. In order to improve the electroconductivity of electrode catalyst layer, this reference discloses the formation of the substrate by using a graphite intercalation compound obtained by intercalating an acid such as sulfuric acid, phosphoric acid, or the like among graphite crystalline layers.